Light harvesting properties of some new heteroleptic dithiocarbimate–diamine/diimine complexes of Ni, Pd and Pt studied as photosensitizer in dye-sensitized TiO2 solar cells

Abstract

This contribution describes the light harvesting efficiencies of new heteroleptic complexes of the form [M(L)(L′)] where L = p-tolylsulfonyldithiocarbimate (p-CH₃C₆H₄SO₂NCS₂²⁻); M = Ni(II), L′ = 2,2′-bipyridine (bpy) (1) or 1,10-phenanthroline (phen) (2) or N,N,N′,N′-tetramethylethylenediamine (tmed) (3); M = Pd(II), L′ = bpy (4) or phen (5) or tmed (6); and M = Pt(II), L′ = bpy (7) or phen (8) or tmed (9). These have been characterized by elemental analysis, IR, ¹H and ¹³C NMR and UV-visible spectroscopies, and 1, 4 and 6 by single crystal X-ray diffraction. UV-visible absorption, electrochemical behavior and structural features of the ligand aromatic sulfonyldithiocarbimate containing free sulfonyl oxygen atoms serving as a typical anchoring group on TiO₂ semiconductor electrode of the nickel complexes enable them to act as potential photosensitizers for solar energy conversion. This study widens the scope for square planar heteroleptic complexes with a suitable combination of metal ions and ligands to be explored as photosensitizers.